What should I do at Thai immigration for a new 90-day registration after getting a new passport?

A new passport is a bit of a pain to be honest. I'm still working through the consequences. New passport in February. Went to immigration to move stamps in March. April had to file 90 day report in person due to new passport. June was time for annual extension so went to bank to request statements, had to register new passport first and was issued with a new bank book, they also required old passport and old bank book. Off to immigration and they wanted photocopies of both passports (even though they'd already moved the stamps) plus they wanted to physically see both passports, they also wanted to physically see both bank books although only photocopies of the new one. Haven't done DLT yet, will do that when my licence renewal is due later in the year. Don't for a moment think that moving stamps means you can lose your old passport

I did this recently in bangkok (I’m on retirement visa). They made me go and get my bank statements from when my extension was issued before they would transfer my stamp to the new passport

Dont forget to update the new passport with the banks

I gotta do mine soon too.

Immigration told me to just bring my old and new passports and they will move the stamps for me.

I was also told I will need to do a new TM30, so need to take my yellow house book, too. Since I have a yellow book, Im responsible for the tm30, so I think this is just to give me a new updated TM30 reciept, to clip in my passport. I would think when they update the passport on the system, it will be updating the current tm30 that's already on the system, so not necessary for people who don't have a yellow book.

So to get an updated 90 report receipt, it might be the same, or they might just do it as part of the process

Take the letter your embassy will give you with your new passport to immigration, they'll move your current stamp to you new passport.

That's it.

Your passport number should be different, remember to update your banks, and your thai drivers license.